that video was really good, and sort of made me realize why i'm such a big fan of his stuff, since it kind of starts with the parts i was aware of at the time and then branches into all the super specialized stuff that came around as i was having a harder time keeping track of it all (especially as i got a little less involved in speedrunning overall, relatively, at a certain point). although i think that's context that's not necessarily obvious in these videos, that pre-srl/gdq sda was a community that wasn't exactly "competitive" in the same way; that is, there weren't a lot of people actively trying for records in the same games at the same times. granted, contra does stand out as such a demanding game that maybe it wouldn't have ever seen a big growth like some of the other nes/snes titles came to in the 2010s, but the fact that it's still presented as such an exciting narrative despite the fact that it's largely just one person at a time striving for the next height is really something.
overall i'm glad to see other documentation of that kind of history, too, since i don't know that the impressions i have are altogether accurate. i remember at first sda was a very niche thing that people thought would never be popular or garner a lot of attention, and the extent to which it's been wholeheartedly embraced in the mainstream on many levels is so cool to me.